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In 1977, Trotter and Moore proved that a poset has dimension at most $3$ whenever its cover graph is a forest, or equivalently, has treewidth at most $1$. On the other hand, a well-known construction of Kelly shows that there are posets of…

组合数学 · 数学 2016-05-05 Gwenaël Joret , Piotr Micek , William T. Trotter , Ruidong Wang , Veit Wiechert

Over the last 30 years, researchers have investigated connections between dimension for posets and planarity for graphs. Here we extend this line of research to the structural graph theory parameter tree-width by proving that the dimension…

It has been known for 30 years that posets with bounded height and with cover graphs of bounded maximum degree have bounded dimension. Recently, Streib and Trotter proved that dimension is bounded for posets with bounded height and planar…

组合数学 · 数学 2018-12-11 Bartosz Walczak

Joret, Micek, Milans, Trotter, Walczak, and Wang recently asked if there exists a constant $d$ such that if $P$ is a poset with cover graph of $P$ of pathwidth at most $2$, then $\dim(P)\leq d$. We answer this question in the affirmative by…

组合数学 · 数学 2015-07-07 Csaba Biró , Mitchel T. Keller , Stephen J. Young

Over the past 10 years, there has been considerable interest in exploring questions connecting dimension for posets with graph theoretic properties of their cover graphs and order diagrams, especially with the concepts of planarity and…

组合数学 · 数学 2023-04-18 Jędrzej Hodor , William T. Trotter

The dimension is a key measure of complexity of partially ordered sets. Small dimension allows succinct encoding. Indeed if $P$ has dimension $d$, then to know whether $x \leq y$ in $P$ it is enough to check whether $x\leq y$ in each of the…

组合数学 · 数学 2019-12-12 Stefan Felsner , Tamás Mészáros , Piotr Micek

We show that height $h$ posets that have planar cover graphs have dimension $\mathcal{O}(h^6)$. Previously, the best upper bound was $2^{\mathcal{O}(h^3)}$. Planarity plays a key role in our arguments, since there are posets such that (1)…

组合数学 · 数学 2022-10-13 Jakub Kozik , Piotr Micek , William T. Trotter

The queue number of a poset is the queue number of its cover graph when the vertex order is a linear extension of the poset. Heath and Pemmaraju conjectured that every poset of width $w$ has queue number at most $w$. The conjecture has been…

组合数学 · 数学 2022-08-29 Sergey Pupyrev

The classical 1991 result by Brightwell and Winkler states that the number of linear extensions of a poset is #P-complete. We extend this result to posets with certain restrictions. First, we prove that the number of linear extension for…

组合数学 · 数学 2018-02-20 Samuel Dittmer , Igor Pak

We prove that every planar poset $P$ of height $h$ has dimension at most $192h + 96$. This improves on previous exponential bounds and is best possible up to a constant factor. We complement this result with a construction of planar posets…

组合数学 · 数学 2018-01-11 Gwenaël Joret , Piotr Micek , Veit Wiechert

Planar posets can have arbitrarily large dimension. However, a planar poset of height $h$ has dimension at most $192h+96$, while a planar poset with $t$ minimal elements has dimension at most $2t+1$. In particular, a planar poset with a…

In 2015, Felsner, Trotter, and Wiechert showed that posets with outerplanar cover graphs have bounded dimension. We generalise this result to posets with $k$-outerplanar cover graphs. Namely, we show that posets with $k$-outerplanar cover…

组合数学 · 数学 2021-05-04 Maximilian Gorsky , Michał T. Seweryn

We prove that every poset with bounded cliquewidth and with sufficiently large dimension contains the standard example of dimension $k$ as a subposet. This applies in particular to posets whose cover graphs have bounded treewidth, as the…

组合数学 · 数学 2025-10-21 Gwenaël Joret , Piotr Micek , Michał Pilipczuk , Bartosz Walczak

Motivated by the study of the dimension of random posets, it was conjectured by Bollob\'as and Brightwell in 1997 that if $P$ is a finite poset whose cover graph contains at most one cycle then its order dimension is at most $3$. In this…

组合数学 · 数学 2025-05-23 Antoine Abram , Adrien Segovia

Heath and Pemmaraju conjectured that the queue-number of a poset is bounded by its width and if the poset is planar then also by its height. We show that there are planar posets whose queue-number is larger than their height, refuting the…

组合数学 · 数学 2018-09-10 Kolja Knauer , Piotr Micek , Torsten Ueckerdt

It has been known for more than 40 years that there are posets with planar cover graphs and arbitrarily large dimension. Recently, Streib and Trotter proved that such posets must have large height. In fact, all known constructions of such…

组合数学 · 数学 2018-12-21 David M. Howard , Noah Streib , William T. Trotter , Bartosz Walczak , Ruidong Wang

Felsner, Li and Trotter showed that the dimension of the adjacency poset of an outerplanar graph is at most 5, and gave an example of an outerplanar graph whose adjacency poset has dimension 4. We improve their upper bound to 4, which is…

组合数学 · 数学 2022-03-09 Marcin Witkowski

The structural parameter twin-width was introduced by Bonnet et al. in [FOCS 2020], and already this first paper included an asymptotic argument bounding the twin-width of planar graphs by a non-explicit constant. Quite recently, we have…

组合数学 · 数学 2022-08-31 Petr Hliněný

Twin-width is a new parameter informally measuring how diverse are the neighbourhoods of the graph vertices, and it extends also to other binary relational structures, e.g. to digraphs and posets. It was introduced just very recently, in…

离散数学 · 计算机科学 2021-07-09 Jakub Balabán , Petr Hliněný

In 1989, Ne\v{s}et\v{r}il and Pudl\'ak posed the following challenging question: Do planar posets have bounded Boolean dimension? We show that every poset with a planar cover graph and a unique minimal element has Boolean dimension at most…

组合数学 · 数学 2022-12-20 Heather Smith Blake , Piotr Micek , William T. Trotter
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